Equipment shutdown

When equipment shutdown becomes necessary, diagnostics must be precise enough to accomplish problem identification and rectification with minimal downtime. 

It generally is recommended, and often required, that gas dcicciiuii systems be installed in a fail-safe manner. That is, if power is disconnected or otherwise interrupted, alarm and/or process equipment shutdown (or other corrective action) should occur. All specific systems should be carefully reviewed, however, to ensure that non-anticipated equipment shutdowns would not result in a more hazardous condition tlian the lack of shutdown of the equipment. If a more hazardous situation would occur with shutdown, only a warning should be provided. As an example, a more hazardous situation might occur if blowout preventers were automatically actuated during drilling operations upon detection of low levels of gas concentrations than if drilling personnel were only warned. 

Concentration levels where alarm and corrective action. should occur vary. If no levels are specified by the authority having jurisdiction, most recommend alarming (and/or actuating ventilation equipment) if combustible gas concentrations of 20 percent LEL (lower explosive limii ) or more are detected. Equipment shutdowns, the disconnecting of dccirical power, production shut-in, or other corrective actions usually are recommended if 60 percent LEL concentrations of combustible gas are detect... 

Mechanical seals are often chosen and designed to operate with environmental controls. If this is the case, check the seal assembly drawing or equipment drawing to ensure that all environmental control piping is properly installed. Before equipment startup, all cooling and heating lines should be operating and remain so for at least a short period after equipment shutdown. 

There are defect limits that are associated with random failure modes. For example, if there is a leak from a mechanical seal on a pump, where do we decide that the leakage is excessive and requires immediate maintenance Vibration analysis severity levels are also typical examples of when do we have severe enough conditions to warrant equipment shutdown and overhaul. In such circumstances, the defect limit is dependent upon individual subjective judgment. 

Take 7 samples from each additional location to further assess each significant event, such as filling or emptying of hoppers and IBCs, start and end of the compression or filling process, and equipment shutdown. This may be accomplished by using process development batches, validation batches, or routine manufacturing batches for approved products. 

Flame arrestor plugs. Insufficient eonfcustior sir Loss of heater equipment shutdown, possible equipment Air intake designed 3 feet above ground Place in operator manual requirements for... 

Safety interlock — A device required to ensure safe start-up and safe operation, and to cause safe equipment shutdown. 

Dissolved air is not readily drawn out of solution. It becomes a problem when temperatures rise rapidly or pressures drop. Petroleum oils contain as much as 12% dissolved air. When a system starts up or when it overheats, this air changes from a dissolved phase into small bubbles. If the bubbles are very small in diameter, they remain suspended in the liquid phase of the oil, particularly in high viscosity oils. This can cause air entrainment, which is characterized as a small amount of air in the form of extremely small bubbles dispersed throughout the bulk of the oil. Air entrainment is treated differently than foam and is typically a separate problem. Some of the potential effects of air entrainment include pump cavitation, spongy and erratic operation of hydraulics, loss of precision control, vibrations, oil oxidation, component wear due to reduced lubricant viscosity, equipment shutdown when low oil pressure switches trip, microdieseling... 

Corrosion occurs in various forms and is promoted by a variety of causes, all related to process operating conditions to which equipment and support structures are subjected. It is a continuous problem that can lead to contaminated process streams. This subsequently leads to poor product quality and unscheduled equipment shutdowns, the consequence of which is reduced production, high maintenance costs, and equipment replacement costs. Minimizing corrosion is a key consideration for the designer and can be accomplished in two ways (1) proper material selection for apparatus, and (2) preventive nraintenance practices. Both of these approaches must be examined. 

At units, any employee shall assess the situation and determine what level of evacuation and what equipment shutdown is necessary to ensure the safety of all personnel, mitigate the environmental impact and potential for equipment/property damage. When in doubt, evacuate. 

Start-up after a significant natural event such as an earthquake or storm that resulted in equipment shutdown. 

Shutdown all process equipment Shutdown all chemical injection Offshore shut subsea production valves... 

A HNOs wash line was disconnected and foe uranyl nitrate feed line was modified so it can be disconnected immediately after charging foe pot. Safety showers in foe immediate area were enclosed. A dry chemical extinguisher was provided in case of fire. Water hoses were removed from the area. These changes create a dry environment they aUow processing 2.C U in a sin e pot with adjacent equipment shutdown. If additional denitration requires use of adjacent equipment, and enclosure for each pot curating at 2.0% U would be needed. 

Why is a manual shutdown needed at all The process requirements specification defines how manual shutdown should be executed from the process perspective. Operators are often provided with manual pushbuttons to initiate equipment shutdown. Operators are expected to initiate trained responses to a variety of shutdown indicators, such as process indications, process alarms, observed events, protective alarms, emergency alarms, or procedures. 

Inspectors should locate hazctfds, identify them in detail, and classify or rank them by seriousness. Immediate action, including equipment shutdown, is appropriate when there is imminent danger. Comprehensive inspection reports allow management to understand and evaluate each situation, so that corrective action decisions can be made promptly. 

Sag A decrease in voltage up to 20 percent below the normal voltage, lasting less than 2.5 s. Also called undervoltage. Can result in memory loss, data errors, flickering lights, and equipment shutdown. 

Equipment Shutdown A system of equipment stoppage and emergency isolation valves that are used to isolate individual equipment within a process unit and prevent the release of potentially toxic material in the event of a fire, rupture, or loss of containment. 

Machine or equipment shutdown must follow the procedures established for the machine or equipment. An orderly shutdown must be used to avoid... 

In an oxygen-deficient atmosphere, iron and steel will react with H2S to form iron sulfide deposits on the smface of the metal. Some iron sulfides (known as pyrophoric iron sulfide) are unstable and, when exposed to air, will undergo a rapid chemical reaction creating an ignition source that should be considered during equipment shutdowns. 

Therefore, using Table 11.5, if there is a toxic gas release, an alarm will sound and the air-conditioning systems will stop. However, the plant equipment will keep mnning. If the toxic gas release is then confirmed, equipment shutdown will be initiated. 

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